Norovirus Infection in Older Adults: Epidemiology, Risk Factors, and Opportunities for Prevention and Control

Abstract

Norovirus is the leading cause of acute gastroenteritis. In older adults, it is responsible for an estimated 3.7 million illnesses; 320,000 outpatient visits; 69,000 emergency department visits; 39,000 hospitalizations; and 960 deaths annually in the United States. Older adults are particularly at risk for severe outcomes, including prolonged symptoms and death. Long-term care facilities and hospitals are the most common settings for norovirus outbreaks in developed countries. Diagnostic platforms are expanding. Several norovirus vaccines in clinical trials have the potential to reap benefits. This review summarizes current knowledge on norovirus infection in older adults.

Keywords: Gastroenteritis; Long-term care; Norovirus; Older adults; Vaccine.

Fig. 1.

Proportion of annual norovirus burden in the United States that occurs in older adults greater than or equal to 65 years old, by outcome. ^aHall and colleagues, 2012; ^bLopman and colleagues, 2011; ^cGastañaduy and colleagues, 2013; and ^dGrytdal and colleagues, 2015.

Fig. 2.

Estimated annual norovirus cases in older adults (≥65 years old) in the United States in 2015, by outcome. To generate case counts, incidence rates by outcome were obtained or calculated from existing literature (^aHall and colleagues, 2012; ^bLopman and colleagues, 2011; ^cGastañaduy and colleagues, 2013; and ^dGrytdal and colleagues, 2015) and multiplied by the US population estimate for older adults in 2015 (47.8 million). For deaths and emergency department visits, 95% CIs are shown in parentheses; for outpatient visits, the average from 2 studies is shown; for hospitalizations, high and low seasonal estimates from 1996 to 2007 are shown; for total illnesses, 95% credible intervals are shown. All numbers are rounded to 2 significant digits. Data collected at the community level are used as proxy for determining total illnesses.